Thanks everyone for your answers.
Check that you own all files in your home directory, especially in ~/.kde4, and that the directories are writable.
Code:
ls -la ~/.kde4
Btw, you can choose a different desktop session on the login screen (press on the wrench or gear symbol). IceWM f.e. should be available and still work.
I’ll try this command and tell you what it brings up.
I hope you took notes on all these sort of things you did to wreck your system. And even then it will be difficult to repair them.
I didn’t but I saved the website where they were, it was Setup FTP Server On openSUSE 13.1 | Unixmen. I remember I additionaly wrote:
chmod 750 /home/username/
chown newuser:ftp-users /home/username/
Migth this have been the problem…? I wanted to make my home folder visible to my other computer…:S
There are two errors. The first one is that for some reason the system can not use your home. Then it tries to use “/” instead, which fails because it has
no permissions there, so you get the second error, which is thus irrelevant.
Thanks for identifying my error, at least its a place where to start searching for the answer 
Undo all you did? Then we try.
Backup your files somewhere and reinstall?
Create new user? Dangerous if you can not undo all the things you did
following unknown advice on internet.
I’m a linux noob user and I yet don’t know to revert the changes I made…
I still hadn’t looked for backing up options, i though that openSUSE automaticaly made control points as windows or some sort of backing up copy.
I don’t know what it can be done to solve the problem, i though that maybe it could be created a user and just asign the home folder of the other
user and work as nothing happened.
Thanks everyone for your help really really much.